18. m[1]v[1] + m[2]v[2] = m[1]w[1] + m[2]w[2], w[1] = w[2], w = 0,14 m·s^-1

   

   19. W = E[p], W[1] = 4905 J, W[2] = 274 J, W[2] -W[1]= 4631 J

   

   20. W = E[k2] – E[k1] = 1760 J

   

   21. E[k] = E[p], v = 6,3 m·s^-1

   

   22. W = E[k] = 67.5 J